
class Queue:
	"""
	Data structure that implements a first-in-first-out (FIFO)
	queue policy. 
	"""
	def __init__(self):
		self.list = []
	
	def push(self,item):
		"""
		Enqueue the 'item' into the queue
		"""
		self.list.insert(0,item)
 
	def pop(self):
		"""
		Dequeue the earliest enqueued item still in the queue. This
		operation removes the item from the queue.
		"""
		return self.list.pop()
	
	def isEmpty(self):
		"""
		Returns true if the queue is empty.
		"""
		return len(self.list) == 0